/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.formats.json;

import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.serialization.DeserializationSchema;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.types.logical.DecimalType;
import org.apache.flink.table.types.logical.RowType;
import org.apache.flink.table.types.logical.utils.LogicalTypeChecks;

import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.DeserializationFeature;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.JsonNode;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.util.Objects;

import static java.lang.String.format;
import static org.apache.flink.util.Preconditions.checkNotNull;

/**
 * Deserialization schema from JSON to Flink Table/SQL internal data structure {@link RowData}.
 *
 * <p>Deserializes a <code>byte[]</code> message as a JSON object and reads
 * the specified fields.
 *
 * <p>Failures during deserialization are forwarded as wrapped IOExceptions.
 */
@Internal
public class JsonRowDataDeserializationSchema implements DeserializationSchema<RowData> {
	private static final long serialVersionUID = 1L;

	/** Flag indicating whether to fail if a field is missing. */
	private final boolean failOnMissingField;

	/**
	 * Flag indicating whether to ignore invalid fields/rows (default: throw an exception).
	 */
	private final boolean ignoreParseErrors;

	/**
	 * TypeInformation of the produced {@link RowData}.
	 **/
	private final TypeInformation<RowData> resultTypeInfo;

	/**
	 * Runtime converter that converts {@link JsonNode}s into
	 * objects of Flink SQL internal data structures.
	 **/
	private final JsonToRowDataConverters.JsonToRowDataConverter runtimeConverter;

	/**
	 * Object mapper for parsing the JSON.
	 */
	private final ObjectMapper objectMapper = new ObjectMapper();

	/** Timestamp format specification which is used to parse timestamp. */
	private final TimestampFormat timestampFormat;

	public JsonRowDataDeserializationSchema(
			RowType rowType,
			TypeInformation<RowData> resultTypeInfo,
			boolean failOnMissingField,
			boolean ignoreParseErrors,
			TimestampFormat timestampFormat) {
		if (ignoreParseErrors && failOnMissingField) {
			throw new IllegalArgumentException(
				"JSON format doesn't support failOnMissingField and ignoreParseErrors are both enabled.");
		}
		this.resultTypeInfo = checkNotNull(resultTypeInfo);
		this.failOnMissingField = failOnMissingField;
		this.ignoreParseErrors = ignoreParseErrors;
		this.runtimeConverter = new JsonToRowDataConverters(failOnMissingField, ignoreParseErrors, timestampFormat)
			.createRowConverter(checkNotNull(rowType));
		this.timestampFormat = timestampFormat;
		boolean hasDecimalType = LogicalTypeChecks.hasNested(rowType, t -> t instanceof DecimalType);
		if (hasDecimalType) {
			objectMapper.enable(DeserializationFeature.USE_BIG_DECIMAL_FOR_FLOATS);
		}
	}

	@Override
	public RowData deserialize(byte[] message) throws IOException {
		try {
			final JsonNode root = objectMapper.readTree(message);
			return (RowData) runtimeConverter.convert(root);
		} catch (Throwable t) {
			if (ignoreParseErrors) {
				return null;
			}
			throw new IOException(format("Failed to deserialize JSON '%s'.", new String(message)), t);
		}
	}

	@Override
	public boolean isEndOfStream(RowData nextElement) {
		return false;
	}

	@Override
	public TypeInformation<RowData> getProducedType() {
		return resultTypeInfo;
	}

	@Override
	public boolean equals(Object o) {
		if (this == o) {
			return true;
		}
		if (o == null || getClass() != o.getClass()) {
			return false;
		}
		JsonRowDataDeserializationSchema that = (JsonRowDataDeserializationSchema) o;
		return failOnMissingField == that.failOnMissingField &&
			ignoreParseErrors == that.ignoreParseErrors &&
			resultTypeInfo.equals(that.resultTypeInfo) &&
			timestampFormat.equals(that.timestampFormat);
	}

	@Override
	public int hashCode() {
		return Objects.hash(failOnMissingField, ignoreParseErrors, resultTypeInfo, timestampFormat);
	}
}
